The anterior and posterior cruciate ligaments of the human knee cooperate, together with other ligaments and soft tissue, to provide both static and dynamic stability to the function of that joint. Often, the anterior cruciate ligament (ACL) is ruptured or torn as a result of, for example, sports related injuries. Consequently, various surgical procedures have been developed for reconstructing the ACL and restoring normal function to the knee.
In many instances, the ruptured ACL may be replaced by substituting a synthetic or harvested graft ligament in its place. More particularly, a graft ligament is attached to either the inside or outside of a tunnel formed in the surrounding bones. The graft is anchored in place by means well known in the art. Once fixed in position, the graft will cooperate with the surrounding tissue and replace the damaged ACL.
It will be appreciated that there is a complex interdependency between the ACL and the other knee ligaments, bones and soft tissue. Consequently, the precise positioning of the graft ACL relative to the surrounding bones is critical to successful reconstruction of the knee joint. In particular, the positioning and formation of the bone tunnel must be precisely controlled by the surgeon.
In U.S. Pat. No. 4,672,957 to Hourahane; U.S. Pat. No. 4,722,331 to Fox; U.S. Pat. No. 4,739,751 to Sapega et al.; U.S. Pat. No. 4,781,182 to Purnell et al.; U.S. Pat. No. 4,920,958 to Walt et al.; U.S. Pat. No. 5,112,337 to Paulos et al.; U.S. Pat. No. 5,154,720 to Trott et al.; and U.S. Pat. No. 5,163,940 to Bourque, there are disclosed a variety of drill guide means for locating a tunnel in the surrounding bones of a knee joint or the like. The foregoing patents further disclose several different methods for using these drill guides. Complete details of the construction and operation of these various drill guides and methods for their use are provided in the above-identified patents, which patents are hereby incorporated herein by reference.
It will, therefore, be understood that drill guide devices such as those taught in the above-referenced patents generally comprise a handle or other support means for holding the drill guide device exterior to the patient's body. Generally, these known drill guide devices also include a probe having a tip that is adapted to be disposed within the knee, at the point where one end of the tunnel is to exit the bone. Typically, a guide sleeve is provided for directing a guidewire or drill into position on the anterior surface of one of the bones surrounding the knee joint. The guide sleeve has its axis more or less aligned to intersect with the aforementioned probe tip and is generally slidable or variable in position relative to the support means. All of the aforementioned parts are held in relation to one another by releasable clamping or locking means known in the art.
In ACL reconstruction, these known drill guide devices are used by first placing the probe tip at or near a predetermined location on the tibial plateau. Next, the drill guide sleeve is both angularly and longitudinally adjusted relative to the probe tip so that the guide sleeve's distal end is directed toward the appropriate position on the anterior surface of the tibia. Once in place, the probe tip and drill guide sleeve are locked in position relative to each other by various means known in the art.
Prior art drill guides require various adjustments to be carried out while the surgeon is holding the device in position within the patient's body. For example, the drill guide sleeve must be released from locking engagement with the supporting member and be pushed into position with one hand, while the drill guide device is held in the surgeon's other hand. In addition, the above-referenced devices also require that the probe be locked in position by tightening a rotatable knob or other locking means. In order to make effective adjustments to the drill guide, the surgeon must observe the effects of these adjustments on the position of the probe tip within the knee. This is typically done by means of a scope or the like being positioned within the knee capsule. Unfortunately, the two-handed adjustments, required by known drill guides, often prohibit the surgeon from adequately maintaining control of the scope. In particular, the surgeon must release the scope in order to adjust the drill guide and vice-versa. This can inhibit proper positioning of the drill guide in the joint.
In any case, once the guide sleeve is adjusted and locked in position, a guidewire (K-wire) is slid through the guide sleeve and securely fastened to the tibia. The K-wire defines the tibial tunnel drilling axis. When the K-wire is seated in position on the tibia, the drill guide sleeve is unlocked and removed, longitudinally, back along the K-wire. Then the support means is removed from around the K-wire, usually by means of a side slot through which the K-wire passes. A cannulated drill is then slid over the K-wire to drill the tibial tunnel according to methods well known to those skilled in the art.
The various two-handed adjustments, required when using prior art drill guides, have significantly limited their effectiveness. Also, if the particular drill guide and probe arrangement initially chosen by the surgeon is not appropriately sized, it is necessary for the surgeon to withdraw the instrument and choose another, thus taking up valuable time during the procedure.